Tomonori Kigawa

Distribution of LHRH in the rat and mouse brain with special reference to the tanycytes

SummaryThe distribution of luteinizing hormone-releasing hormone (LHRH) was studied in the rat and mouse brain by means of light and electron microscopic immunohistochemistry using the peroxidase-antiperoxidase method. An immunoreactive product to LHRH antiserum was found near the blood vessels of the vascular organ of the lamina terminalis. In the arcuate nucleus-median eminence region, an immunoreactive material occurred bilaterally in the hypothalamic tissue around the tuberoinfundibular sulci. Electron microscopy revealed that immunoreactive fibers observed light microscopically contain numerous granules 100–130 nm in diameter. No immunoreactive product was located in the tanycytes of the median eminence, the perikarya of hypothalamic neurons, and the parenchyma of several circumventricular organs (subfornical organ, subcommissural organ, pineal organ, area postrema).

Immunohistochemical and immunoelectron microscopic study of an amylase-producing, CA19-9 positive ovarian mucinous cystadenocarcinoma

A 75-year-old woman with a right ovarian tumor revealed high levels of serum amylase and CA19-9 which decreased to within normal limits after the operation. A histopathological study of surgically excised tumor tissue revealed a mucinous cystadenocarcinoma. The tumor was composed of three elements: adenoma, adenoma with low potential malignancy, and adenocarcinoma. Using the light microscopic indirect immunoperoxidase technique for amylase and CEA, and the Avidin-Biotin affinity technique for CA19-9 and CA12-5, the amylase and CA19-9 were stained in the cytoplasm of the adenoma and adenocarcinoma although CEA was stained only in the cytoplasm of the adenocarcinoma. An ultrastructural study using the immunoperoxidase method revealed that CA19-9 was positive in the apical portion of the tumor cells and amylase was positive in the entire secretory vesicles of the tumor cells. Furthermore, ciliated tumor cells derived from fallopian tube epithelium were not observed in the light and electron microscopic specimens.

The Mechanism of Induction of Ovulation by Bromocriptine in Euprolactinemic Anovulation

It has been well documented that ovulation was induced by Bromocriptine treatment in euprolactinemic anovulation. The present study has been carried out to clarify the underlying mechanism. 28 patients with euprolactinemia (PRL less than 25 ng/ml) were treated with a 5 mg daily administration of Bromocriptine. Ovulation was induced in 13 cases, which were determined by their BBT charts. In the ovulated cases, PRL secreting capacities were increased, determined by TRH administration. On the other hand, PRL secreting capacities were normal in the anovulated cases. The studies of the circadian secretion of PRL revealed that a nocturnal hyperprolactinemic state occurred for several hours in the ovulated cases, which was not seen in the anovulated cases. From these results, the mechanism of induction of ovulation by Bromocriptine in euprolactinemic anovulation exists on the suppression of the increased PRL secreting capacity, which may be related to the occulted hyperprolactinemia at night. Ovulated cases by Bromocriptine are seemingly euprolactinemia, but in truth they may be a kind of hyperprolactinemia.

The effects of bromocriptine on the pulsatile pattern and the circadian profile of gonadotropins and testosterone secretion in normal adult men

To investigate the effects of bromocriptine on the secretion mechanism of pituitary gonadotropins and testosterone, 5 mg of bromocriptine was administered to five young adult men who were normal in their endocrinological states. Blood samplings were taken from two hours before until six hours after the administration every 15 min., and after that, blood samplings were continued until 21 hours every one hour by an intravenous indwelling catheter. Serum FSH, LH, prolactin and testosterone levels were determined by RIA, and the changes of the pulsatile patterns of FSH and LH, and the circadian profile of these hormones by the administration of bromocriptine were analysed. Serum prolactin levels decreased significantly (p less than 0.005) from two hours after the administration of bromocriptine and remained in a very low range until the end of the experiment. The basal levels of FSH showed a significant decrease from two to six hours after the administration (p less than 0.005). Also the basal levels of LH showed a significant decrease from two to six hours after the administration (p less than 0.005). However, the basal levels of serum FSH and LH did not show significant decreases after that until the end of the experiment. No significant change was observed in the amplitude or the frequency of the pulsatile patterns of FSH and LH until six hours after the administration of bromocriptine. The serum levels of testosterone were also significantly decreased from two to six hours after the administration (p less than 0.005), but they did not show a significant decrease after that until the end of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes of serum gonadotropin concentrations in fetal and neonatal rat following castration.

Changes of serum concentrations of LH were measured in fetal and neonatal rats following castration. Intact fetal and neonatal male rats showed low levels of serum LH concentration. Though serum LH levels of male rats casterated on the 20th day of gestation did not significantly increase by the 22nd day of fetal age, serum levels of neonatal male rats increased 2-to 3-fold 3 days following castration at all ages studied. The increase was greater in 4-day-old male rats than in 1-day-old males. The increase of serum LH after castration was also found in 4-day-old male rats castrated on the 20th day of gestation. In contrast, serum levels of 1-day-old neonatal female rats did not increase 3-days after castration. These observations suggest sex differences in maturation of the gonadal-hypophyseal feedback mechanism.